The present invention relates to a method and apparatus for facilitating the connection of tubulars used in the oil and gas exploration and extraction industries. More specifically, the invention relates to an apparatus for facilitating the handling of tubulars into or out of a well bore.
In the construction of oil or gas wells it is usually necessary to line the well bore with a string of steel pipes commonly known as tubular or tubing or generically as oil country tubular goods (“OCTG”). For purposes of this application, such steel pipes shall hereinafter be referred to as “tubular OCTG”. Because of the length of the tubular OCTG required, individual sections of tubular OCTG are typically progressively added to the string as it is lowered into a well from a drilling rig or platform. The section to be added is restrained from falling into the well by some tubular engagement means, typically a spider or the like, and is lowered into the well to position the threaded pin of the tubular OCTG section adjacent the threaded box of the tubular OCTG in the well bore. The sections are then joined by relative rotation of the sections until such time as the desired total length has been achieved.
It is common practice to use a single joint elevator to transfer the tubular from the V-Door to a position above the rotary table whereby it can engage the tubular currently constrained in the rotary table. This traditional method and equipment types have been used extensively around the world for a period in excess of fifty years. While this method is in daily use it is a very dangerous task with personnel having to perform manual lifting and securing of the single joint elevator whilst it is tethered to a steel cable under high loads. The method of restraining the door or latch of the single joint elevator from opening under loads is a manually fitted mechanical pin. However this method relies solely on the operator to ensure the safety restraining pin is secured correctly. Because the single joint elevator can swing violently in rough or bad weather conditions it is not unusual for the safety restraining pin to be dislodged thereby placing the personnel on the rig floor under immense danger of possible falling objects or even a dropped tubular OCTG.
In more recent times, where a top drive may be used, this is a top drive rotational system used for drilling purposes. Where a top drive system is used to make the connection, the use of a set of hydraulically controlled bail arms have been employed to aid the positioning of the manual single joint elevator. However this can be problematic, due to the configuration of the top drive bails in so much as it protrudes or extends insufficient distance on the rig floor and it does not remove the manual intervention to secure the single joint elevator, safety restraining pin and thereby the safety hazard. It is therefore known to make use of an apparatus commonly referred to as a single joint elevator suspended from a steel wire cable or winch assembly used to transfer the tubular from the V-Door to the rotary table or mousehole.
The intention of the present invention is to offer a much-improved method for single joint elevator or tubular handling device for running tubular OCTG into a borehole without the shortfalls in the tools available today.